Patent GB-439502-A (GB)
Title: Improvements in or relating to electric switches or circuit-breakers
IPC: H01H33/02
Filed: 1934-06-07
Abstract: 439,502. Switchgear structures; liquid-break switches. REYROLLE & CO., Ltd., A., Hebburn-on-Tyne, CLOTHIER, H. W., 3, Jesmond Park West, Newcastle-on-Tyne, and FAWCETT, A. E., 102, Sunderland Road, Cleadon Park Estate, South Shields. June 7, 1934, No. 16953. [Class 38 (v)] Switches, latching and unlatching ; earthing parts of. -A circuit - breaker comprises a tank containing insulating liquid in which the main contacts are immersed, fixed terminals in the tank connected to the external circuit, and isolating conductors normally connecting the fixed terminals respectively with the main contacts but movable longitudinally to break such connections and connect the associated main contacts to earthed contacts within the tank. Means are provided for effecting such longitudinal movement, the arrangement being such that one or each isolating conductor can be moved independently of the other. As shown, two such switches are combined into a structure for controlling a teeconnection to a ring main, each of which switches has a removable tank A filled with oil to the level A<3> and suspended from a cover B forming the base of a chamber B<1> having partitions B<2>. Each switch has a pair of fixed terminals per phase, of which the inner D<1> are interconnected by conductor D<2> and connected by conductor D<3> to the tee-connection and the outer terminals D are connected to the respective sides of the ring main. D, D<1> both terminate in sockets D<6> in the inner parts E of twopart insulators, the outer parts E<1> of which carry annular metal caps E<2> which support the fixed main contacts F which co-operate with movable contacts F<1> carried on a bar F<2>. Also slidable within caps E<2> are isolating conductors G, G<1> normally engaging sockets D<6> and carried on insulating brackets G<2>, which are slidable on rods H<2> forming a part of a metal frame carrying earthing contacts H for the contacts F. The conductors G are raised and lowered by means of a spindle K<1> to which can be clutched an arm J' linked at J<3> to a crank J<1> which is mounted on shaft J<2> and connected to G<2> by a link J. Conductor G<1> is operated by similar parts L<1>-L<4>, the arm L<4> being fixed to spindle K<1>. The parts J, J<1>, L, L<1> are duplicated at the back of the structure. The clutch is of the tooth kind and is set by a pointer N<2> so that, when engaged, the conductors G, G<1> will be operated to isolating position but, when disengaged, only conductors G<1> will be operated to isolate the tee-connection. A suitable interlock ensures operation of the clutch only when the conductors G are in closed position, and further interlocks prevent lowering of the tank when conductors G are closed, and closure of G<1> when the tank is lowered. The bar F<2> carrying the movable contacts of all the phases is linked at Q to cranks Q <1> on a shaft Q<2> which has a pin-and-lug connection Q<3>, T<1> with a shaft T<2> carrying an operating handle T<3> and pointer T<4>, the handle T<3> being removable, if desired, and adapted to fit the shaft K<1> which carries a pointer K<3>. The rear crank Q<1> carries a cam Q<5> co-operating with a locking plate R which in turn co-operates with a cam L<6> on the rear crank L<1>, so locking conductors G<1> against movement unless the main switch is off, and preventing the latter from being moved into a testing (" off ") position except when G<1> are in the earthed position. To reach the testing position, a locking bolt S<2> is unpadlocked and depressed to allow a projection Q' on Q<1> to pass by a projection S<3>, the movement of the handle T<3> to this position also unlocking the tank, whereby a testing lead can be connected at E<3> to the cap E<2>. To earth the ring main from the normal position, the main contacts are opened, the clutch freed, and conductors G<1> moved to earthed position, whereupon the main contacts are reclosed. The fixed terminals may alternatively be brought in at the bottom or the side walls, or one may be brought in at the bottom and the other at the top. The isolating conductors may alternatively be operated by separate operating handles. Specification 199,461, [Class 40 (v)], is referred to,